University of Naples, Portici, Italy.
Mol Nutr Food Res. 2009 Dec;53(12):1540-50. doi: 10.1002/mnfr.200900447.
The toxicity of dietary acrylamide (AA) depends on its biotransformation pathways, in which phase I cytochrome P-450 enzymes transform AA into glycidamide. The phase II enzyme glutathione_S_transferase (GST) catalyses the conjugation of AA with glutathione (GSH). GST induction by phytochemicals like sulforaphane (SFN) plays a role in chemoprevention. Here, the effect of SFN on the detoxification of AA through GSH conjugation was studied in Caco-2 cells. GSH adducts with AA and SFN were synthesized, identified by NMR and quantified by LC-MS/MS. Caco-2 cells were treated with either 2.5 mM AA, 10 microM SFN or the combination of both for 24 h. Concentrations of GSH conjugates (GSH-AA, GSH-SFN, SFN-GSH-AA), AA and SFN were analysed by LC-MS/MS. GSH contents and GST activity were determined photometrically. GST activity was increased after treatment of the cells with SFN (38+/-6%, p< or =0.05) or AA (25+/-4%, p< or =0.05). GSH concentrations decreased after all treatments. Quantitative data of GSH adduct formation showed that the reaction between GSH and SFN is favoured over that between GSH and AA. The data suggest that SFN might impair the GSH-dependent detoxification of AA by SFN-GSH adduct formation and, thus, lower the GSH concentrations available for its reaction with AA.
膳食丙烯酰胺（AA）的毒性取决于其生物转化途径，其中 I 相细胞色素 P-450 酶将 AA 转化为缩水甘油酰胺。II 相酶谷胱甘肽 S-转移酶（GST）催化 AA 与谷胱甘肽（GSH）的结合。植物化学物质如萝卜硫素（SFN）对 GST 的诱导在化学预防中发挥作用。在这里，研究了 SFN 对 Caco-2 细胞中通过 GSH 结合解毒 AA 的影响。合成了与 AA 和 SFN 的 GSH 加合物，通过 NMR 鉴定，并通过 LC-MS/MS 定量。用 2.5 mM AA、10 μM SFN 或两者的组合处理 Caco-2 细胞 24 小时。通过 LC-MS/MS 分析 GSH 加合物（GSH-AA、GSH-SFN、SFN-GSH-AA）、AA 和 SFN 的浓度。通过比色法测定 GST 活性和 GSH 含量。用 SFN（38+/-6%，p≤0.05）或 AA（25+/-4%，p≤0.05）处理细胞后，GST 活性增加。所有处理后 GSH 浓度均降低。GSH 加合物形成的定量数据表明，GSH 与 SFN 之间的反应优先于 GSH 与 AA 之间的反应。数据表明，SFN 可能通过 SFN-GSH 加合物的形成损害 GSH 依赖的 AA 解毒作用，从而降低 GSH 浓度，使其与 AA 反应。
